Hydraulic feed mechanism



Oct. 16, 1951 R. E. PRICE HYDRAULIC FEED MECHANISM 2 SHEETS -SHEET 1Filed Aug. 26, 1948 llmcntor RA-LPH E. PRICE Gttomeg Oct. 16, 195] PR|cE2,571,610

HYDRAULIC FEED MECHANISM Filed Aug. 26, 1948 2 SHEETSSHEET 2 inventorEAL PH E. Pklcz' (Ittomeg Patented Oct. 16, 1951 UNITED STAT HYDRAULICFEED MECHANISM Ralph E. Price, Highfield, Md., assignor to Landis ToolCompany, Waynesboro, Pa.

Application August 26, 1948, Serial No. 46,280

17 Claims. 1 This invention relates to feed mechanisms for grindingmachines, particularly centerless grinders.

The primary object of this invention is to provide an automatic feedcycle. By this is meant a cycle which will be repeated as often asdesired without attention from the operator.

A further object is to provide a control mechanism which will functionto initiate the cycle as well as cause a dwell at each end of the feedmovement.

A further object is to provide a work ejecting mechanism operable inconnection with said feed mechanism.

Figure 1 is perspective showing the structure of the feed mechanism.

Figure 2 shows a hydraulic diagram for a feed mechanism and a workejecting mechanism for a centerless grinder.

Numeral Ill indicates a grinding wheel base slidably mounted on a bed IIfor movement toward or from operative position. A grinding wheel I2 isrotatably mounted in said base. Said movement may be effected manuallyor by power.

The manual feeding means consists of a hand wheel [5 for driving throughsuitable gearing to a worm gear IS on an axially slidable shaft I]. Saidworm gear engages a worm wheel I8 on feedscrew shaft I9. All thismechanism is carried in wheel base Ill.

The feedscrew I9 is in operative engagement with a nut 20 in bed II.

Rotation of hand wheel I5 causes rotation of worm l6, worm wheel l8, andfeedscrew I9 in nut 20, thus causing feedscrew to move relative to thenut and carrying the wheel base [0 with it.

The power means for moving said wheel base consists of a piston 25 atthe opposite end of shaft H from hand wheel I5. Said piston i slidablymounted in a cylinder 26. The stroke of said piston and hence the feedmovement of the wheel support In may be adjusted by means ofadjustablestop 21.

Fluid under pressure may be introduced alternately to opposite ends ofsaid cylinder as will be described more in detail later.

Movement of piston 25 in response to the introduction of fluid underpressure into cylinder 25 results in an endwise movement of shaft I1 andworm [6. Under these circumstances, worm I6 acts as a rack and thuscauses rotation of worm wheel I8 and, hence, feedscrew l9.

While the feed mechanism disclosed herein is applicable to grindingmachines of many types, I prefer to illustrate it as applied to acenterless grinder. Accordingly, the diagram Figure 2 in:

cludes a control wheel 30 peripherally opposed to grinding wheel I2. Themethod .of driving the grinding wheel at the conventional speed and thecontrol wheel at a much slower speed is well known and need not be shownhere.

A work piece 35 is supported between the peripheral surfaces of thegrinding and control wheels on a work rest 36.

Fluid under pressure is directed alternately through lines and 4| toopposite ends of cylinder 26 to move grinding wheel I2 toward and fromoperative position. Said fluid under pressure is supplied by a pump 50through line 5| to a reversing pilot valve 52. Valve 52 directs fluidalternately to opposite ends of a cycle control valve 60 and a reversingvalve 10.

Valve 52 is connected through rod 53 to one end of a lever 54. Saidlever is pivoted at an intermediate point 55. The other end is in theform of a yoke having spaced opposing adjusting screws 56 and 51.Between said screws is a dog member 80 attached to timer piston 8|. Eachend of said valve has an axial bore 82R and 821. and an intersectingradial bore 83R and 831., the function of which will be discussed later.

Pilot valve 52 receives fluid under pressure from pump 50 through line5| and directs it alternately through lines TI and I2 to opposite end ofreversing valve I0. It also directs said fluid alternately through linesBI and 62 to opposite ends of valve Bil.

Reversing valve I0 receives fluid from pump 50 through line EI and inthe position shown is directing said fluid through line 40 to the headend of cylinder 26. Exhaust fluid from the opposite end of cylinder 26passes through line 4| to valve In which directs it to one of theexhaust ports of said valve. When valve 1!] is shifted to the left,fluid from line 5| passes through line M to the right end of cylinder 26and shifts piston 25 to the left. Exhaust fluid from the left end of thecylinder may pass freely through line 28, check valve 29, lines 40 and42 to valve I9 and the left end exhaust passage of said valve. Thispermits a rapid movement of wheel base II! to place grinding wheel I2 ingrinding position. When piston 25 closes off line 28, the only outlet isthrough line 40 and throttle valve 43 to valve 10, and the left-handexhaust port. Throttle valve 43 may be set to provide a suitablegrinding feed.

Valve While valve I0 directs fluid under pressure to actuate feed piston25 to the right for backing ofi' wheel I2, valve 60 in the right-handposition shown directs fluid under pressure through line 63 to shifttiming piston 8| in cylinder 84 to the right. Said valve receives itssupply of fluid from line through line 58. A selector valve 59 in line58 serves to render valve 55 inoperative so far as the actuation oftiming piston 8| is concerned. In one position the fluid under pressureis supplied to valve 60, and in the other position of valve 59 theportion of line 58 between valve 60 and valve 59 is connected withexhaust through valve 59. In this position of valve 59, reversing pilotvalve 52 must be actuated manually.

Said piston 8| has a dog member 80 operable between screws 56 and 5! inreversing lever 54. As piston 8| moves to the right, exhaust fluid firstpasses through line 65 to valve 69 and the left exhaust port therein. Assaid piston closes line 55, exhaust fluid must by-pass through throttlevalve 66, which is set to delay the actuation of reversing lever 54 foran interval suitable for loading a work piece into the machine. Piston8| has axial passages at each end indicated as 82R and 821.respectively. Said passages connect with radial passages indicated as8311 and'831. respectively.

The period during which movement of piston 5| is controlled by Valve 66provides time'for backing ofi grinding wheel I2, removing a finishedwork piece and placing an unground work piece in the machine. As soon aspaSsage 83R comes into line with line .65, exhaust fluid from therighthand end of cylinder 84 may pass freely throu h line 55 and valve60 to the left end exhaust port. Piston .8! then moves quickly to theend of its stroke and dog 89 engages screw 5'! to shift lever 54 andvalve 52 to the left. For a continuous cycle, screw 5'! is adjusted sothat dog 86 engages it just after passage 83R comes into line with line65. If it is desired to have the wheel base l0 stop in the inoperativeposition, screw 51 may be backed off so that dog 85 does not engage itat the end of the movement of piston 3|. When screw 51 is adjusted inthis manner, the wheel base I0 will reverse automatically at the end ofthe grinding operation; but it will stop in the back position andremain" there until the operator shifts lever 54 to the left.

Assume that valve 59 and screw 51 are adjusted for a complete automaticcycle. When pilot valve 52 is shifted to the left, valves 50 and arealso shifted to the left. Valve '10 directs fluid through line 4| to theright-hand end of cylinder'26 and piston moves to the left, turningfeed-screw 9 at a rapid rate until piston 25 cuts off line 28 throughwhich exhaust fluid may pass freely to check valve 29, line 42, line 40and the left end exhaust line from valve l8. Thereafter, exhaust fluidfrom the left end of cylinder 26 is passed through line 40 and throttlevalve 43 which determines the rate of movement of piston 25 during thegrinding operation. From valve 13 fluid passes through another portionof line 40 to valve 10 which directs it to the left exhaust port of saidvalve.

Exhaust fluid in line 40 also acts on the left end of valve 90 to shiftit to the right against spring 9|. Check valve 29 is held in closedposition by a spring, not shown, slightly heavier than spring 9| so asto assure suflicient pressure toactuate valve 8|]. Valve 95 is held inthis position by exhaust pressure during the entire feeding stroke. F

At the end of the feeding stroke, piston 25 comes to rest againstadjustable stop 21. In the absence of movement of piston 25, exhaustpressure in line 40 disappears and spring 9| returns valve 90 to theleft-hand position.

In the left-hand position of valve 60 fluid under pressure from line 58is directed through line I00 to valve 90. So long as valve is in therighthand position, the fluid in line I00 can move no further. At theend of the feeding stroke, valve 90 returns to the left-hand position,connects line I00 with line |Ei| leading to the right-hand end of timingcylinder 84 and starting the timing movement of piston 8|. 'Thus, thetiming period begins not with the movement of piston 25, but after thepiston reaches the end of its stroke and the feeding movement of thegrinding wheel is stopped. Timing piston 8|, therefore, times only thespark out period. The duration of this period is determined by throttlevalve I02 through which exhaust fluid from the left end of cylinder 84and line 63 must pass to reach line 64, which is connected through valveBl] with the left end exhaust port of said valve. A description of thequick initial and final movements of piston 8| has been omitted here,since it is identical with that described in connection with themovement of this piston in the opposite direction.

Work ejector The ejecting mechanism isshown for the purpose ofillustration as a cylinder |0 having slidably mounted therein a piston Apiston rod H2 on said piston'exten'ds from the cylinder into the spacebetween the grinding wheel l2 and control wheel 35. Said piston may beactuated by fluid under pressure at the left end of said cylinder tomove said piston and piston rod to the right against the action ofspring '||3. When so moved, rod H2 pushes work piece 35 out of thegrinding throat. "Piston III is actuated in'timed relation with themovement of wheel base ID toward and from operative position. This timedrelation is effected by hydraulic connection between cylinder 26 and apair of valves H5 and H5. These valves are shifted from one position toanother hydraulically. However, they control a supply of air underpressure for the operation of piston I. The supply of air under pressureenters valve I I5 throughlin'e' I25 from which it is directed throughline I25 to valve H6. Valve H6 connects line 126 with line I21 leadingto cylinder H). The only time air from line |25 can reach cylinder H0 iswith valve I I5 in the right-hand position as shown and valve H6 in theleft-hand position or opposite to that shown.

During the feeding stroke of piston 25, fluid under pressure is directedfrom valve 10, line 4| to the right end of cylinder 26. The fluid underpressure from line 4| also passes through line I20 to the right end ofvalve I I5 and through throttle valve |2| to the right end of valve II6. Valve I5 is shifted to the left position immediately and cuts offthe supply of air from line I25 through line I'Zi; to valve Hi. Themovement of valve 1 I6 is delayed due to the setting of throttle valveI2 I, sothat the air is sure to be shut off before said valve reachesthe left-hand position in which it connects the air supply of line|26'with line 121, leading to ejector cylinder Ill. It is necessary todelay the action of valve H6 so that it does not move simultaneouslywith valve H5; or even ahead of it, and thus connect said ejectorcylinder with the air supply before it has been cut of! by valve I5.Thus, out of time operation of the ejector is prevented. 1

After a work piece has been ground and piston 25 moves from left toright to withdraw the grinding wheel'from grinding position, said pistonuncovers line I30 leading to the left-hand end of valves H5 and H6.Valve H5 moves immediately to the right and connects air line I25 withline I26. Valve I I6 moves more slowly than valve H5 because of throttlevalve I2I through which the exhaust fluid from valve H6 must pass. Thus,before valve H6 has an opportunity to break the connection between lineI25 and I21, ejector piston III and rod H2 have been moved to the rightand work piece 35 is ejected. Piston II I is held in the right-handposition until valve IIB reaches its right-hand position, connectingline I21 with exhaust port I28. Spring H3 then shifts piston I I I androd I I2 to the left in which position rod H2 serves as a locating meansfor the next work piece.

I claim:

1. In a machine tool, a hydraulic system including a motor for shiftinga machine element, a supply of fluid under pressure for actuating saidmotor, a reversing mechanism for determining the direction of movementof said motor, including a pilot valve and a reversing valve, anactuating mechanism for determining the interval during which said motorremains stationary at either end of its movement, including, a motor foractuating the pilot valve and a reversing valve also actuated by saidpilot valve for directing fluid under pressure alternately to oppositeends of said pilot valve operating motor.

2. In a machine tool, a hydraulic system including a motor for shiftinga machine element, a supply of fluid under pressure for actuating saidmotor, a reversing mechanism for determining the direction of movementof said motor, including a pilot valve and a reversing valve, anactuating mechanism for' determining the interval during which saidmotor remains stationary at either end of its movement, including amotor for actuating the pilot valveand a second reversing valve alsoactuated by said pilot valve for directing fluid under pressurealternately to opposite ends of said pilot valve operating motor, andmeans for cutting off the supply of fluid to said second reversing valvewhereby to prevent operation of said timing mechanism.

3. In a hydraulic system, a motor for shifting a machine element, asupply of fluid under pressure for actuating said motor, a reversingmechanism for determining direction of movement of said motor, a timingmechanism for determining the interval during which the motor isstationary at either end of its movement, a timing valve operated bysaid reversing mechanism for actuating said timing mechanism and a valvebetween said timing valve and one end of said timing mechanism operableat the end of said motor movement in one direction for initiatingoperation of said timing mechanism.

4. In a machine tool, a hydraulic system including a motor for shiftinga machine element, a supply of fluid under pressure for actuating saidmotor, a reversing mechanismv for determining the direction of movementof said motor, a timing mechanism for determining the interval duringwhich said motor remains stationary at either end of its movement, atiming valve for directing fluid to actuate said timing mechanism, and apressure operated valve between said timing valve and said timingmechanism for preventing operation of said timing mechanism until saidmotor has moved to a predetermined position.

5. In a machine tool, a hydraulic system, a motor for shifting a machineelement, a supply of fluid under pressure for actuating said motor, areversing mechanism for determining the direction of movement of saidmotor, a timing mechanism for determining the interval during which saidmotor remains stationary at either end of its movement, a timing valvefor directing fluid to actuate said timing mechanism, and a pressureoperated valve between said timing valve and said timing mechanism andresponsive to movement of said motor for determining the starting timeof said timing mechanism.

6. In a machine tool, a hydraulic system including a motor for shiftinga machine element, a supply of fluid under pressure for actuating saidmotor, a reversing mechanism for determining the direction of movementof said motor, including a pilot valve and a reversing valve, anactuating mechanism for determining the interval during which said motorremains stationary at either end of its movement, including a motor foractuating the pilot valve and a reversing valve also actuated by saidpilot valve for directing fluid under pressure alternately throughopposite ends of said pilot valve operating motor, and a valve actuatedby exhaust fluid from said first motor during the feeding movement forpreventing operation of said pilot valve actuating motor until the endof said feeding movement.

7. In a hydraulic system, a motor for shifting a machine element, asupply of fluid under pressure for actuating said motor, a reversingmechanism for determining direction of movement of said motor, a timingmechanism for determining the interval during which the motor isstationary at either end of its movement, a timing valve operated bysaid reversing mechanism for actuating said timing mechanism, a springloaded cutoif valve between said timing valve and timing mechanism whichis operated by back pressure of exhaust fluid from said motor in onedirection of its movement to prevent actuation of the timing mechanismuntil said motor reaches the end of its stroke in one direction.

8. In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a workpiece, a cutting tool on said support, power means for efiectingsaidmovement including a piston and cylinder, a supply of fluid underpressure therefor, a work ejecting mechanism, and connections betweensaid cylinder and said work ejecting mechanism for actuating saidmechanism, including a pair of valves, one of which is shifted instantlyto direct fluid t the second valve, said second valve directing saidfluid to said ejector and then moving to position to connect saidejector with exhaust.

9. In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a workpiece, a cutting tool on said support, power means for effecting saidmovement including a piston,

and cylinder, a supply of fluid under pressure therefor, a work ejectingmechanism and connections between said cylinder and said work ejectingmechanism for actuating said mechanism including a separate source offluid under pressure for actuating said ejector, a valve for controllingthe flow of said fluid to said ejector and means for actuating saidvalve after said tool has started to move from operative position.

10. .In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a workpiece, a cutting tool on said support, power means for 7 effecting saidmovement including a piston and cylinder, 9. supply of fluid underpressure therefor, a work ejecting mechanism and connections betweensaid cylinder and said work ejecting mechanism for actuating saidmechanism including a separate source of fluid under pressure foractuating said ejector, a valve for controlling the flow of said fluidto said ejector and a conduit for conducting fluid under pressure fromsaid cylinder to actuate said ejector valve.

11. A grinding machine including peripherally opposed grinding andcontrol wheels, a work rest for rotatably supporting a work piece inoperative relation to said wheels, a work positioning and ejectingmechanism for locating a work piece in and ejecting it from saidoperative relation with said wheels, including a piston and a cylindertherefor, means for effecting a feeding movement of one of said wheelstoward the other, including a second piston and cylinder and a conduitfrom a point in said feed cylinder intermediate the ends thereof forconducting fluid under pressure to effect operation of said ejectorpiston after a predetermined movement of said feed piston.

12. In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a workpiece, a cutting tool on said support, power means for effecting saidmovement including a piston and cylinder, a supply of fluid underpressure therefor, a work ejecting mechanism, and connections betweensaid cylinder and said work ejecting mechanism for actuating saidmechanism, including a pressure-operated valve operable at a controlledrate in one direction and having spaced ports for first directing fluidunder pressure to actuate said ejector and thereafter directing saidfluid to reset said ejector.

13. In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a 'WOI'kpiece, a cutting tool on said support, power means for effecting saidmovement including a piston and cylinder, a supply of fluid underpressure therefor, a, work ejecting mechanism, and connections betweensaid cylinder and said work ejecting mechanism for actuating saidmechanism, including a valve operable at a controlled rate for firstdirecting fluid under pressure to actuate said ejector and thereafterdirecting fluid to reset said ejector, and a second pressure operatedvalve for controlling the supply of fluid to said ejector valve.

14. In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a workpiece, a cutting tool on said support, power means for effecting saidmovement including a piston and cylinder, a supply of fluid underpressure therefor, a work ejecting mechanism including a piston andcylinder and an ejector actuated by said piston, resilient means forurging said piston in one direction, a pressure-operated valve oper- 8able at=a controlled rate and having spaced ports for first directingfluid to actuate said ejector piston and thereafter permitting thedischarge of fluid from said ejector cylinder independently of themovement of said first-mentioned piston.

15. In a machine tool, a base, a support slidably mounted on said basefor a movement toward and from operative position relative to a workpiece, a cutting tool on said support, power means for effecting saidmovement including a piston and cylinder, a supply of fluid underpressure therefor, a work ejecting mechanism, and connections betweensaid cylinder and said work ejecting mechanism for actuating saidmechanism, including a valve operable after said piston moves said tooltoward inoperative position for directing fluid under pressure toactuate said ejector and means for retarding the movement of said valvewhereby fluid under pressure is first directed to said ejector cylinderand thereafter said ejector cylinder is connected to an exhaust line.

16. In a machine tool, a tool support, a feed mechanism for moving saidsupport toward and from operative position, comprising a piston andcylinder, a supply of fluid under pressure for driving same, controlmeans including a reversing valve, a timing mechanism comprising a freepiston having a lost motion connection with said reversing valve, meansactuated at the end of the movement of said feed piston toward operativeposition to initiate the operation of said timing piston, and meansactuated by said timing piston after a predetermined interval forshifting said reversing valve to return said tool to inoperativeposition.

17. In a machine tool, a tool support, a feed mechanism for moving saidsupport toward and from operative position comprising a piston andcylinder, a supply of fluid under pressure for driving same, controlmeans including a reversing valve, a timing mechanism, means actuated inresponse to a drop in exhaust pressure at the end of the movement ofsaid piston for shifting said tool into operative position to initiatethe operation of said timing mechanism, and means actuated by saidtiming mechanism after a predetermined interval for shifting saidreversing valve to return said tool to inoperative position.

RALPH E. PRICE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,000,614 Roehm May 7, 19352,004,426 Booth et al June 11, 1935 2,117,917 Silven May 17, 19382,214,394 Wood Sept. 10, 1940 2,295,342 Graf et al. Sept. 8, 19422,364,300 Koplin et a1. Dec. 5, 1944 2,419,940 Balsiger et a1 May 6,1947

